Re: [dpdk-dev] [RFC PATCH 5/5] test: add few eBPF samples

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

-----Original Message-----
> Date: Thu, 8 Mar 2018 01:30:02 +0000
> From: Konstantin Ananyev <konstantin.ananyev@intel.com>
> To: dev@dpdk.org
> CC: Konstantin Ananyev <konstantin.ananyev@intel.com>
> Subject: [dpdk-dev] [RFC PATCH 5/5] test: add few eBPF samples
> X-Mailer: git-send-email 1.7.0.7
> 
> Add few simple eBPF programs as an example.
> 
> Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> diff --git a/test/bpf/mbuf.h b/test/bpf/mbuf.h
> new file mode 100644
> index 000000000..aeef6339d
> --- /dev/null
> +++ b/test/bpf/mbuf.h
> @@ -0,0 +1,556 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2010-2014 Intel Corporation.
> + * Copyright 2014 6WIND S.A.
> + */
> +
> +/*
> + * Snipper from dpdk.org rte_mbuf.h.
> + * used to provide BPF programs information about rte_mbuf layout.
> + */
> +
> +#ifndef _MBUF_H_
> +#define _MBUF_H_
> +
> +#include <stdint.h>
> +#include <rte_common.h>
> +#include <rte_memory.h>

Is it worth to keep an copy of mbuf for standalone purpose?
Since clang is already supported, I think, if someone need mbuf then
they can include DPDK headers. Just thinking in maintainability
perspective.

> diff --git a/test/bpf/t1.c b/test/bpf/t1.c
> new file mode 100644
> index 000000000..e587d5e5b
> --- /dev/null
> +++ b/test/bpf/t1.c
> @@ -0,0 +1,54 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2018 Intel Corporation
> + */
> +
> +/*
> + * eBPF program sample.
> + * Accepts pointer to first segment packet data as an input parameter.
> + * analog of tcpdump -s 1 -d 'dst 1.2.3.4 && udp && dst port 5000'
> + * (000) ldh      [12]
> + * (001) jeq      #0x800           jt 2    jf 12
> + * (002) ld       [30]
> + * (003) jeq      #0x1020304       jt 4    jf 12
> + * (004) ldb      [23]
> + * (005) jeq      #0x11            jt 6    jf 12
> + * (006) ldh      [20]
> + * (007) jset     #0x1fff          jt 12   jf 8
> + * (008) ldxb     4*([14]&0xf)
> + * (009) ldh      [x + 16]
> + * (010) jeq      #0x1388          jt 11   jf 12
> + * (011) ret      #1
> + * (012) ret      #0
> + *
> + * To compile:
> + * clang -O2 -DRTE_CACHE_LINE_SIZE=64 -I${RTE_SDK}/${RTE_TARGET}/include \

Does not look like, this application is accessing any DPDK stuff, If so,
Should we remove -DRTE_CACHE_LINE_SIZE=64 -I${RTE_SDK}/${RTE_TARGET}/include?

> + * -target bpf -c t1.c
> + */
> +
> +#include <stdint.h>
> +#include <net/ethernet.h>
> +#include <netinet/ip.h>
> +#include <netinet/udp.h>
> +
> +uint64_t
> +entry(void *pkt)
> +{
> +	struct ether_header *ether_header = (void *)pkt;
> +
> +	if (ether_header->ether_type != __builtin_bswap16(0x0800))
> +		return 0;
> +
> +	struct iphdr *iphdr = (void *)(ether_header + 1);
> +	if (iphdr->protocol != 17 || (iphdr->frag_off & 0x1ffff) != 0 ||
> +			iphdr->daddr != __builtin_bswap32(0x1020304))
> +		return 0;
> +
> +	int hlen = iphdr->ihl * 4;
> +	struct udphdr *udphdr = (void *)iphdr + hlen;
> +
> +	if (udphdr->dest !=  __builtin_bswap16(5000))
> +		return 0;
> +
> +	return 1;
> +}
> +
> diff --git a/test/bpf/t2.c b/test/bpf/t2.c
> new file mode 100644
> index 000000000..6228609c5
> --- /dev/null
> +++ b/test/bpf/t2.c
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2018 Intel Corporation
> + */
> +
> +/*
> + * eBPF program sample.
> + * Accepts pointer to struct rte_mbuf as an input parameter.
> + * cleanup mbuf's vlan_tci and all related RX flags
> + * (PKT_RX_VLAN_PKT | PKT_RX_VLAN_STRIPPED).
> + * Doesn't touch contents of packet data.
> + * To compile:
> + * clang -O2 -DRTE_CACHE_LINE_SIZE=... -I${RTE_SDK}/${RTE_TARGET}/include \
> + * -target bpf -Wno-int-to-void-pointer-cast -c t2.c
> + */
> +
> +#include <stdint.h>
> +#include <stddef.h>
> +#include "mbuf.h"

Can we take Cache line size from rte_config.h which anyway included in
mbuf.h through rte_memory.h?

> +
> +uint64_t
> +entry(void *pkt)
> +{
> +	struct rte_mbuf *mb;
> +
> +	mb = pkt;
> +	mb->vlan_tci = 0;
> +	mb->ol_flags &= ~(PKT_RX_VLAN_PKT | PKT_RX_VLAN_STRIPPED);
> +
> +	return 1;
> +}
> +
> -- 
> 2.13.6
>